Ok so recently the devs said that the new islands couldn't be added to the game for monile :(. However, what if they did this, their should be several maps and in the settings you can choose what islands you want their, maybe have a limit like 2 for mobile. Then not only do you get the islands, but more customization in the game. This is just an idea not an actual thing (yet) and would most likely be a butt ton of work so keep that in mind, upvote or comment if you think this is a good idea.
But data isn't te probably it's CPU use I'm talking about and yes it would take a crud load of data , but Eh I could deal. @JetstreamAeroEngineering
You would still have to use the Same amount of data if not more to have multiple maps as having it all in one open world. Either way the game would be unplayable for most mobile users.